Mixtures comprising polymers and photocatalytically active fillers have been disclosed in the prior art.
EP 1 955 767 A1 discloses a mixture comprising photocatalysts and organic polymers, such as polyacetals, polyethylene, polypropylene, polystyrene, polyvinyl chloride, nylon-type polymers, polycarbonates, etc. The photocatalysts used preferably comprise titanium dioxide particles, which have a coating composed of non-porous silicon dioxide.
JP 2007-277433 discloses a polymeric material comprising at least one thermoplastic polymer and photocatalytically active material, applied to carbon powder as support material. The photocatalytically active material according to that document is titanium dioxide in the anatase form.
JP 2000-017096 discloses foamed foils composed of thermoplastic resins, which have titanium dioxide as antibacterial coating. Silanes can have been applied as surface modifier on the surface of the titanium dioxide.
JP 2000-204194 discloses a process for the production of polymer compositions which comprise titanium dioxide as photocatalyst. The titanium dioxide has, for example, a coating of silicon dioxide. The ratio of polymer to titanium dioxide is from 97:3 to 20:80.
JP 09/225321 A discloses a photocatalytically active body composed of titanium dioxide in the anatase form. The titanium dioxide used in that composition is present between two porous layers of another inorganic compound, such as silicon dioxide.
JP 2005-097608 A discloses a polyolefin film which comprises photocatalyst particles, where the photocatalyst particles are mixed crystalline oxides comprising titanium dioxide and silicon dioxide. That document does not disclose any core-outer layer photocatalysts or any use in thermoplastic polymers.